'''23:54, 29 October 2012 (CDT):''' Coded and tested a basic wireless control protocol that is used between a "base station" and the robot. Right now, motor commands can be sent from the base station, and as more sensors are added, the robot will be able to send data back to the base station. Useful data may include sensor values, current state of the internal state machine, decision-making choices, etc.

'''23:54, 29 October 2012 (CDT):''' Coded and tested a basic wireless control protocol that is used between a "base station" and the robot. Right now, motor commands can be sent from the base station, and as more sensors are added, the robot will be able to send data back to the base station. Useful data may include sensor values, current state of the internal state machine, decision-making choices, etc.

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'''22:38, 5 November 2012 (CST):''' Untethered the robot (battery powered, wirelessly conrtolled), and realized that the current design is not mechanically feasible. Because of it's long shape, with the wheels and motors located in the rear, there is very little weight applied to the wheels to create friction. During testing, the wheels just spun without moving the robot at all. A new design is currently in the works.

Overview

The initial version of CAESAR Bot.

C.A.E.S.A.R. stands for "Cute And Edgy Sumo Attack Robot", and is my team's entry into the Mini-Sumo Robot Competition hosted by Auburn University SPaRC. The objective of the competition is to build a small, autonomous robot that is capable of pushing a competing robot out of a sumo ring. The requirements for entry into the competition are as follows:

The robot must fully fit inside a 10 cm by 10 cm starting area, but there are no height restrictions.

The robot must weigh no more than 0.5 kg.

The robot must use up to two of the Solarbotics GM9 motors with the RM2 Motor drop-in replacement for driving the robot.

Ideas

Chassis

Currently (v0.1), the chassis design is a long wedge that initially starts off vertically (in order to fit in the starting area), which then falls down at the start of the match. This design gives C.A.E.S.A.R Bot a nice long ramp that can get underneath the opponent's robot’s wheels for easier pushing. It will most likely be built out of lasercut plywood or acrylic, depending on the strength of each material.

Enemy Detection

Enemies need to be detected in order to design an effective algorithm to push the other robot out of the ring. Below are some of the sensor possibilities (will probably end up using a combination of both):

Sharp IR Sensor:

Benefits:

Long line of sight

Only one input pin needed

Fast measurements

Drawbacks:

Narrow beam width

Not effective against dark colored robots

Moderately costly

Measurements can be noisy, depending on the environment

Cost: $12.95 (one on hand)

Ping Sensor (Ultrasonic Distance Sensor):

Benefits:

Accurate

Wide beam width

Only two input pins needed

Low cost

Drawbacks:

Not effective against fuzzy robots

Echo problems

Cost: $2.39 (not purchased)

Edge Detection

Pololu QTR-1RC Reflectance Sensor:

Benefits:

Easy-to-use

Accurate

Quick

Drawbacks:

Small range

Cost: 3 @ $4.14 each (not purchased)

Materials

In v0.1, the C.A.E.S.A.R. Bot chassis is designed to be lasercut out of a single 9"x12" piece of material. The v0.1 testing prototype was made out of 5.2mm plywood, but the design can be easily modified to work with acrylic sheet.

Other materials needed for v0.1 include:

(4x) #6 Bolts - 1 1/2"

(4x) #6 Flat Washers

(4x) #6 Lock Washers

Electronics

In order to control and power the robot, a microcontroller, motor driver, and power source are needed. We are going to try to use parts that are currently on hand:

Microcontroller: Arduino Pro Mini 328 16MHz

Cost: $10.38 (purchased)

Motor Driver: L293 Compact Motor Driver

Cost: $4.29 (purchased)

Battery: 1300mAh LiPo 7.4v 2S 25C battery

Cost: $5.36 (purchased)

Cost Analysis

Listed below are the estimated costs associated with v0.1 of the robot. This does not include the cost of entry into the competition, and the motors are included with the entry fee.

Part

Cost Each

Qty. Needed

Qty. Purchased

Sharp IR Sensor

$12.95

1

1

Ping Sensor

$2.39

1

0

Pololu QTR-1RC

$4.14

3

0

5.2mm Plywood

$0.90/sq.ft.

1

1

Arduino Pro Mini

$10.38

1

1

L293 Motor Driver

$4.29

1

1

1300mAh LiPo

$5.36

1

1

Total

$48.69

Progress Log

22:49, 30 September 2012 (CDT): I have created and cut out a basic chassis for the robot, and made some modifications to the design to add stability. Basic motor control has been programmed for the Arduino and motor board.

23:33, 1 October 2012 (CDT): Tested and wrote code for the Ultrasonic Distance Sensor. It works surprisingly well, and should be well-suited for enemy detection.

23:33, 24 October 2012 (CDT): Successfully programmed the Arduino Pro Mini with the USB-serial adapter I had gotten a while while back. Was also able to set up a wireless test-link (ping/pong) between the Pro Mini and an Arduino Uno using two NRF24L01+ modules, so that the robot can soon be wirelessly controlled for testing/other purposes.

23:54, 29 October 2012 (CDT): Coded and tested a basic wireless control protocol that is used between a "base station" and the robot. Right now, motor commands can be sent from the base station, and as more sensors are added, the robot will be able to send data back to the base station. Useful data may include sensor values, current state of the internal state machine, decision-making choices, etc.

22:38, 5 November 2012 (CST): Untethered the robot (battery powered, wirelessly conrtolled), and realized that the current design is not mechanically feasible. Because of it's long shape, with the wheels and motors located in the rear, there is very little weight applied to the wheels to create friction. During testing, the wheels just spun without moving the robot at all. A new design is currently in the works.